Transmission Problem??

[BajaSportsmobile]

Originally Posted by carringb

In 2WD low? Pretty sure the front axle doesn't have any torque in that situation....

Both rear axles (right and left) as you were referencing an open differential. Did I misunderstand?

[carringb]

Originally Posted by BajaSportsmobile

Both rear axles (right and left) as you were referencing an open differential. Did I misunderstand?

Gotcha. Still only matters with equal traction under both tires. I just think it's an axle looking for an opportunity to break, since "middle of nowhere" I assume is not a paved driveway.

[scatter]

I'm aware of the possibility of axle damage carringb and all the other reasoning you've mentioned, but the pinon nut is something I've never considered. Probably a pretty rare occurrence, but sure something to be aware of and to consider. Thanks for bringing it up.
You're right, there is lots of torque (that's why we're using low gears to hold the rig back) in a situation like this. When traversing a steep, up or down, rocky road there is also lots of slippage happening in the drive tires and when that happens then even more torque on the tire, and axle, of the tire with traction. 4x4 is the only way to go in a situation like that.
I usually have the rig in 4x4 when traveling steep and very rocky roads, but in this particular case the road was fairly smooth dirt and I was traveling in 4x2 high. I came to this really steep downhill, but short, section and I just shifted it into low range for additional compression braking. Too lazy to get out and turn the hubs....
I do occasionally use 4x2 low range on some of the really steep paved roads up here in the mountains where low gear in high range won't hold the rig back. I'm comfortable with that and think the chances of rear end damage is nil. Correct?? Plus, when on pavement I don't like to lock the front hubs. Seems to me that activating the front drive line without locking the hubs really doesn't accomplish much.

Bajasportsmobile - I was going so slow and the hill was so steep and rocky that I didn't look at the speedo. I have in the past, and while in low range there is a big difference in actual speed and the indicated speed. I can't remember what it's been, but has to do with the transfer case ratio.

Lots of good info here and I appreciate it. Especially the part about not worrying about my transmission.

[daveb]

I've had my foot jump off the brake and on to the throttle launching the van in 2wd low. Kind of freaked me out and now if I'm on a trail, I lock the hubs and when needed take it in and out of 4x4 as I see fit. But I still do use 2wd low... just a bit more careful these days. If the terrain is rough and even if it's easy enough for 2wd I just go into 4x4.

[BajaSportsmobile]

Originally Posted by scatter

Bajasportsmobile - I was going so slow and the hill was so steep and rocky that I didn't look at the speedo. I have in the past, and while in low range there is a big difference in actual speed and the indicated speed. I can't remember what it's been, but has to do with the transfer case ratio.

I believe your Atlas II is a 4.0 to 1 reduction in low range. If your speedo and ecu are getting mixed signals or out of range, I can see it going into some temporary "limp mode". Turning it off and restarting would clear that.

I doubt there is a mechanical problem with your transmission.

By the way, the transmission has no idea if your transfer case is in 2wd Lo or 4wd Lo so that has nothing to do with the issue.

[scatter]

I believe your Atlas II is a 4.0 to 1 reduction in low range. If your speedo and ecu are getting mixed signals or out of range, I can see it going into some temporary "limp mode". Turning it off and restarting would clear that.

I doubt there is a mechanical problem with your transmission.

By the way, the transmission has no idea if your transfer case is in 2wd Lo or 4wd Lo so that has nothing to do with the issue.

Yup on all of the above. By the way, just checked driving to town and at 20 mph, by GPS, speedo indicated around 60 mph.

[BajaSportsmobile]

Originally Posted by scatter

Yup on all of the above. By the way, just checked driving to town and at 20 mph, by GPS, speedo indicated around 60 mph.

Maybe you were going "too fast" for first gear...

[scatter]

Could be, but nothing that I haven't done before. Them gremlins can pop up anywhere.